diff --git a/src/Psalm/Internal/Analyzer/ClassAnalyzer.php b/src/Psalm/Internal/Analyzer/ClassAnalyzer.php
index 518035fa1..38f5dc122 100644
--- a/src/Psalm/Internal/Analyzer/ClassAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/ClassAnalyzer.php
@@ -1518,10 +1518,10 @@ class ClassAnalyzer extends ClassLikeAnalyzer
                     ),
                     $storage->suppressed_issues + $this->getSuppressedIssues()
                 )) {
-                    return false;
+                    // fall through
                 }
 
-                return null;
+                return false;
             } else {
                 if (!$codebase->traitHasCorrectCase($fq_trait_name)) {
                     if (IssueBuffer::accepts(
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php
index 281893791..4cbd63dd9 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php
@@ -58,6 +58,7 @@ class ArgumentAnalyzer
         ?FunctionLikeParameter $function_param,
         int $argument_offset,
         PhpParser\Node\Arg $arg,
+        ?Type\Union $arg_value_type,
         Context $context,
         array $class_generic_params,
         ?TemplateResult $template_result,
@@ -66,8 +67,6 @@ class ArgumentAnalyzer
     ) {
         $codebase = $statements_analyzer->getCodebase();
 
-        $arg_value_type = $statements_analyzer->node_data->getType($arg->value);
-
         if (!$arg_value_type) {
             if ($function_param && !$function_param->by_ref) {
                 if (!$context->collect_initializations
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentsAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentsAnalyzer.php
index b33f66f4f..12095252b 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentsAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentsAnalyzer.php
@@ -10,6 +10,7 @@ use Psalm\Internal\Analyzer\Statements\Expression\ExpressionIdentifier;
 use Psalm\Internal\Analyzer\Statements\Expression\Fetch\ArrayFetchAnalyzer;
 use Psalm\Internal\Analyzer\StatementsAnalyzer;
 use Psalm\Internal\Codebase\InternalCallMapHandler;
+use Psalm\Internal\Stubs\Generator\StubsGenerator;
 use Psalm\Internal\Type\Comparator\UnionTypeComparator;
 use Psalm\Internal\MethodIdentifier;
 use Psalm\Internal\Type\TemplateResult;
@@ -92,6 +93,8 @@ class ArgumentsAnalyzer
             $args = array_reverse($args, true);
         }
 
+        $codebase = $statements_analyzer->getCodebase();
+
         foreach ($args as $argument_offset => $arg) {
             if ($function_params === null) {
                 if (self::evaluateAribitraryParam(
@@ -155,8 +158,6 @@ class ArgumentsAnalyzer
                 $toggled_class_exists = true;
             }
 
-            $codebase = $statements_analyzer->getCodebase();
-
             if (($arg->value instanceof PhpParser\Node\Expr\Closure
                     || $arg->value instanceof PhpParser\Node\Expr\ArrowFunction)
                 && $template_result
@@ -569,6 +570,35 @@ class ArgumentsAnalyzer
 
         $function_param_count = count($function_params);
 
+        if (count($function_params) > count($args) && !$has_packed_var) {
+            for ($i = count($args); $i < count($function_params); $i++) {
+                if ($function_params[$i]->default_type
+                    && $function_params[$i]->type
+                    && $function_params[$i]->type->hasTemplate()
+                    && $function_params[$i]->default_type->hasLiteralValue()
+                ) {
+                    ArgumentAnalyzer::checkArgumentMatches(
+                        $statements_analyzer,
+                        $cased_method_id,
+                        $self_fq_class_name,
+                        $static_fq_class_name,
+                        $code_location,
+                        $function_params[$i],
+                        $i,
+                        new PhpParser\Node\Arg(
+                            StubsGenerator::getExpressionFromType($function_params[$i]->default_type)
+                        ),
+                        $function_params[$i]->default_type,
+                        $context,
+                        $class_generic_params,
+                        $template_result,
+                        $function_storage ? $function_storage->specialize_call : true,
+                        $in_call_map
+                    );
+                }
+            }
+        }
+
         foreach ($args as $argument_offset => $arg) {
             $function_param = $function_param_count > $argument_offset
                 ? $function_params[$argument_offset]
@@ -594,8 +624,10 @@ class ArgumentsAnalyzer
                 }
             }
 
+            $arg_value_type = $statements_analyzer->node_data->getType($arg->value);
+
             if ($method_id === 'compact'
-                && ($arg_value_type = $statements_analyzer->node_data->getType($arg->value))
+                && $arg_value_type
                 && $arg_value_type->isSingleStringLiteral()
             ) {
                 $literal = $arg_value_type->getSingleStringLiteral();
@@ -622,6 +654,7 @@ class ArgumentsAnalyzer
                 $function_param,
                 $argument_offset,
                 $arg,
+                $arg_value_type,
                 $context,
                 $class_generic_params,
                 $template_result,
diff --git a/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php b/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
index 23de525a0..d2af5a152 100644
--- a/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
+++ b/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
@@ -689,6 +689,13 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements PhpParse
 
             $functionlike_storage = array_pop($this->functionlike_storages);
 
+            if ($functionlike_storage->docblock_issues
+                && (strpos($this->file_path, 'CoreGenericFunctions.phpstub')
+                    || strpos($this->file_path, 'CoreGenericClasses.phpstub'))
+            ) {
+                throw new \UnexpectedValueException('Error with core stub file docblocks');
+            }
+
             if ($functionlike_storage->has_visitor_issues) {
                 $this->file_storage->has_visitor_issues = true;
             }
@@ -2646,6 +2653,8 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements PhpParse
                     new CodeLocation($this->file_scanner, $stmt, null, true)
                 );
 
+
+
                 continue;
             }
 
diff --git a/src/Psalm/Internal/Stubs/CoreGenericFunctions.phpstub b/src/Psalm/Internal/Stubs/CoreGenericFunctions.phpstub
index bc428b890..e236efd91 100644
--- a/src/Psalm/Internal/Stubs/CoreGenericFunctions.phpstub
+++ b/src/Psalm/Internal/Stubs/CoreGenericFunctions.phpstub
@@ -634,6 +634,19 @@ function preg_replace($search, $replace, $subject, int $limit = -1, &$count = nu
  */
 function preg_replace_callback($search, $replace, $subject, int $limit = -1, &$count = null) {}
 
+/**
+ * @psalm-pure
+ * @template TFlags as int
+ *
+ * @param string $pattern
+ * @param string $subject
+ * @param mixed $matches
+ * @param TFlags $flags
+ * @param-out (TFlags is 256 ? list<list<array{string, int}>> : list<list<string>>) $matches
+ * @return int
+ */
+function preg_match_all($pattern, $replace, &$matches, int $flags = 1) {}
+
 /**
  * @psalm-pure
  *
diff --git a/tests/FunctionCallTest.php b/tests/FunctionCallTest.php
index 7a0260fc0..eefa0959a 100644
--- a/tests/FunctionCallTest.php
+++ b/tests/FunctionCallTest.php
@@ -1322,6 +1322,19 @@ class FunctionCallTest extends TestCase
                         if ($one && array_values($one) === array_values($two)) {}
                     }'
             ],
+            'pregMatchAll' => [
+                '<?php
+                    /**
+                     * @psalm-pure
+                     *
+                     * @return list<list<string>>
+                     */
+                    function extractUsernames(string $input): array {
+                        preg_match_all(\'/@[a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}(?!\w)/\', $input, $matches);
+
+                        return $matches;
+                    }'
+            ],
         ];
     }